The birth rate is dropping to at/below replacement across most of the world. Take Iran, for example. It has a lower birth rate than Europe. Not what you'd expec

The birth rate is dropping to at/below replacement across most of the world. Take Iran, for example. It has a lower birth rate than Europe. Not what you'd expect, but it happens to every nation that develops a modern economy. At a certain point, it makes more sense for young parents to concentrate their resources on one or two children, rather than hedge their bets against disease and famine and war by having many children - and more importantly, having a child at all is sufficiently expensive and difficult that many adults just opt out of it.